Among the various mass transportation systems that are often considered by cities to meet growing demand—e.g., in terms of operational efficiency, construction costs, cityscape footprint—monorail systems possess a number of advantages. For example, in contrast to trolleys that travel on tracks that are weaved through city streets, monorails transport people and/or cargo above roads and thus do not significantly impact the flow of automobile traffic. Moreover, since monorail systems do not require the excavation of enormous tunnels many feet under existing streets, they also display various cost advantages over subway systems.
There are, however, some challenges that must be faced in constructing a monorail system. For instance, deep and/or wide holes often must be dug to plant the thick/strong/wide columns that are typically needed to withstand large imbalanced forces/moments caused by the monorail—which further implies relatively costly constructions, relatively long periods of traffic detours, and relatively large streetscape ‘footprints’. To get a rough idea of the potential magnitude of such imbalanced forces/moments one only has to imagine a 30-ton monorail suspended from a rail that is fifteen feet to one side of the column supporting it; and, then further imagine the even greater imbalance that could occur if that same rail is curved and the monorail is traveling at (even) a moderate speed. Accordingly, there is a need for a system(s), method(s), and/or device(s) to at least partially counterbalance one or more such moments/forces.
Another issue that often arises—at least in a number of air cushion-based monorail systems—is the inherent inefficiency resulting from employing a relatively thick layer/cushion of air between the (e.g., steel) bearing and (e.g., steel) rail, which is often needed to prevent (or at least minimize) rail-bearing contact, since thick air layers/cushions often imply relatively large air losses (from between the bearing and rail), relatively large air losses generally mean a lot of air must be pumped in (between the bearing and rail) to replace the air lost, and a fair amount of power consumption is typically required as a result. In fact, one can easily imagine the unwanted contact that would otherwise occur (between the bearing and the rail) without a relatively thick layer of air if a longitudinally straight metal bearing with a curved/concave cross section were traveling along a cylindrically shaped rail at portions of the rail that are curved, undulated, sagging, and/or simply not manufactured with precision. Accordingly, there is a need for a bearing(s), bearing system(s), and/or method(s) that is(are) relatively more efficient in the usage of air. Even more generally, a technology(ies) that serves to reduce air usage and/or power usage, such as in the context of an air bearing, would be desirable.
On a related note, since a number of prior air bearings reflect mirrored shapes of their corresponding rails (e.g., a cylindrical-shaped bearing that matches, or has a slightly larger radius than, its corresponding cylindrical-shaped rail) there is a need for a bearing(s), bearing system(s), and/or method(s) that does(do) not involve so much ‘sandwiching’ of the air layer between the bearing and rail. For instance, it is believed that certain friction-related losses can, at least sometimes, occur in at least some of these ‘mirrored’ bearing-rail relationships, such as if either of the mated surfaces is not very smooth.
A further issue that is similar to the air layer/cushion thickness issue above is the fact linear induction motors (‘LIMs’)—which are employed in a number of mass transportation systems—need to maintain a close distance to the rail to avoid thrust losses since these can otherwise become quite substantial. Accordingly, a system(s), method(s), and/or device(s) that tend(s) to automatically maintain relatively efficient LIM-rail distances in one or more ways that are different than prior art systems would be potentially advantageous as well.
An additional issue that some track-based systems, like monorails, commonly confront is the unwanted separation of components, such as two portions of a rail/track that are meant to be adjacent. This may occur for a variety of reasons, such as changes in temperature (e.g., winter versus summer conditions) or a slight shifting of the foundation supporting such structures. While this issue does not necessarily lead to significant inefficiencies in all track-based systems, any gaps between two rails in a monorail system that relies on an air-cushion/layer would generally be undesirable. Thus, a system(s), method(s), and/or device(s) that can at least minimize, if not eliminate, such gaps would also have inherent value.
Finally, since columns supporting rails, as well as the rails themselves, are susceptible to potential damage from tremors and/or resonance, a system(s), method(s), and/or device(s) that has(have) the ability to reduce one or both of these would also be potentially advantageous.